1 不是质数

#include <cstdio>
#include <vector>
#include <unordered_set>
#include <functional>

// #include <bits/stdc++.h>

using namespace std;

using ll = long long;

bool isZs(ll x) {
	for (ll i = 2; i * i <= x; ++i)
		if (x % i)
			continue;
		else
			return false;
	return x > 1;
}

int main() {
	unordered_set<ll> zs = {2, 3, 5, 7};
	
	ll res = 0;
	for (ll i = 1; i <= 20210605; ++i) {
		if ( isZs(i) ) {
			ll x = i;
			while (x) {
				if (!zs.count(x % 10))
					goto NO;
				x /= 10;
			}
			++res;
//			printf("%d Yes\n", i);
			NO:
				;
		}
	}
	
	printf("%lld\n", res);
	
	return 0;
}